Pump device, for instance for front and rear wheel driven motorcycle

ABSTRACT

A pump arrangement is arranged to be driven by a rotating shaft and comprises a piston arrangement that generates a flow pulse. The piston arrangement has pistons that move axially forward and backward. An actuating device is connected to the rotating shaft and drives the piston arrangement. The actuating device has a cross section of constant width with at least three corners. During rotation caused by the rotating shaft, the actuating device is arranged to interact with carrier devices that are associated with the pistons.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority to and is a U.S. National Phase of PCT International Application Number PCT/SE2006/000742, filed on Jun. 19, 2006, designating the United States of America and published in the English language, which claims priority under 35 U.S.C. § 119 to Swedish Application Number 0501415-4, filed on Jun. 20, 2005. The disclosures of the above-referenced applications are hereby expressly incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a pump arrangement for front and rear wheel driven motorcycles that are powered by a high pressure hydraulic flow. More particularly, the present invention relates to a pump arrangement that is driven by a rotating shaft and that comprises a piston arrangement that generates a flow pulse or pulse of medium, which piston arrangement has pistons that move forward and backward in a substantially longitudinal direction, and an actuating device for the pistons arranged in association with the shaft.

2. Description of the Related Art

Motorcycles can use a hydraulically operating pump to supply power for propulsion to the front wheel. Such motorcycles are shown, for example, in application PCT/SE2004/001782, which published as WO 2005/061261 on Jul. 7, 2005.

With this type of pump, there is a need for a pump that works efficiently but that has small external dimensions. The space for the pump is often limited and there is a need to be able to reduce the external dimensions by, for example, 40-60% compared with the external dimensions of currently known corresponding pumps. In spite of this need for reduced size, the pump should be able to operate with a very large output (for example, 20 kW) and should have a reliable and functional construction that can work with long service intervals. There is also a desire to be able to arrange for parts of the pump arrangement, for example, the oil supply, the oil cooler, the oil filter, etc, to be common to more than one hydraulic system and also to arrange the pump in such a way that serves the respective hydraulic systems without creating any interaction between these systems. In other words, there is a desire to create a modular construction.

SUMMARY OF THE INVENTION

In some embodiments, the actuating device comprises a cross section having a curve of constant width, a so-called Reuleaux cross section, with at least three corners. In a Reuleaux cross section, the distance between each corner and the peripheral surface that is directly across from this corner is essentially the same, irrespective of the rotational position of the cross section around the rotating shaft. The actuating device is also arranged to interact, via the peripheral surface of the cross section, with the carrier devices associated with the piston, during its rotation caused by the shaft.

In a preferred embodiment, the carrier devices are in the form of yokes that are generally rotationally fixed but that are capable of axial movement in the longitudinal direction of associated piston. The actuating device rotates in relation to flanges of the yokes in response to the rotation of an input shaft. The rotation of the actuating device causes the pistons to move in an axial direction that is generally normal to the rotational axis of the actuating device. The pistons move axially within spaces or recesses provided for the pistons in a housing/body, which spaces or recesses can be considered to be cylinders. Preferably there are two or more pistons and associated carrier devices. In some embodiments, the actuating device is provided with an additional layer on the peripheral surface with the layer being rounded off at the corners of the actuating device in order to allow less damaging interaction between the inner surfaces of the flanges and the corners during the rotation. Preferably, the number of corners is odd and can be three, five, seven, etc, in number.

In some embodiments that are arranged and configured in accordance with certain features, aspects and advantages of the invention, the pump comprises a housing with a first partial space for the actuating device and one or more second partial spaces for the cylinders. The one or more second partial spaces receive the pistons and the pistons reciprocate within the one or more second partial spaces. The rotating shaft extends into the first partial space and the actuating device is connected to the portion of the shaft that extends into the first partial space. The carrier devices with the yokes are arranged in the said first partial space. Preferably, the yokes reciprocate in the longitudinal directions of the pistons in response to the rotation of the actuating device, which is rotated by the shaft. In addition, in association with the one or more second partial spaces, the housing comprises outlets for the generated outflow of medium and inlets through which medium is introduced from a low pressure side in a hydraulic system. Each piston can be provided with an internal passage for medium that is open when the piston is in a first longitudinally displaced position in the relevant second partial space. The passage is closed when the piston is in a second position at least partially protruding from the relevant second partial space. An opening and closing arrangement is utilized for each piston. The pump can, in addition, comprise a valve arrangement that carries the flow pulses or pulses of medium generated by the pistons to a hydraulic motor for driving the drive unit for the motorcycle's front wheel. The valve arrangement can comprise spring-loaded devices, for example shims, arranged to be able to be opened and closed to pass parts of or all of the flow pulses to the front wheel's drive unit. Additional further developments will be apparent from the following description and subsidiary claims.

Preferably, the pump can be assembled from reliable components. The pump preferably works with flow pulses or pulses of medium that are close together and that have reduced amplitude, for example considerably reduced amplitude, in comparison to pumps that operate at one pulse per revolution. The new pump therefore can be easily constructed to be very resistant to wear and it is generally less damaging to other system components. The effects on the system thus can be reduced considerably and many advantages can be obtained as far as volume is concerned. No special measures need to be taken as far as space is concerned in connection with the location of the pump. In the case of motorcycles, for example, the pump can be arranged in hitherto unutilized spaces, in spite of the fact that these have minimal volumes, due to the greatly reduced size of the pump.

BRIEF DESCRIPTION OF THE DRAWINGS

A currently proposed embodiment of an arrangement will be described below with reference to the attached drawings in which:

FIG. 1 shows a side view of a motorcycle with front and rear wheel drive with a pump located in a hitherto unutilized space;

FIG. 2 schematically shows in top plan view parts of the motorcycle according to FIG. 1;

FIG. 3 shows, in the form of a diagram, pulse generation with one pulse per revolution according to a previous pump construction;

FIG. 4 shows, in the form of a diagram, pulse or medium generation with several pulses per revolution;

FIG. 5 schematically shows a carrier device with a cross section in the form of a Reuleaux triangle that can interact with a first piston arrangement;

FIG. 6 schematically shows the carrier device interacting with a second piston arrangement;

FIGS. 7 and 8 schematically show the carrier device interacting with a piston;

FIG. 9 shows in longitudinal section a construction of a pump with an actuating device, a piston and a carrier device in relation to a rotating shaft;

FIG. 10 shows in horizontal section a piston arrangement and duct system in the housing of the pump of FIG. 9;

FIG. 11 shows in vertical section a valve arrangement for taking pulses of medium or flow pulses generated by the piston arrangement to an outlet duct to the hydraulic unit of the front wheel; and

FIGS. 12 and 13 show in horizontal view constructions of the Reuleaux triangle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 schematically show a motorcycle 1. The motorcycle 1 can be of the type that comprises a rear wheel drive combined with a front wheel drive (not specifically shown) specially, cf. the abovementioned PCT-document. The rear wheel is driven in a conventional way by a motor 2 and a chain arrangement 3. The motorcycle's rear wheel is indicated by 4 and the front wheel is indicated by 5. The rear wheel 4 is arranged to drive a hydraulic pump 6 via the chain 3, which hydraulic pump 6 is arranged in a space behind the motor 2 and forward of an attachment point 7 for the rear wheel's pivot arm 8. The space 9 preferably is located on the left side of the motorcycle where the pump has a natural position from a functional point of view due to its small external dimensions. In this space 9, the pump 6 does not obstruct the use of the motorcycle. Other parts of the motorcycle generally comprise well known components and therefore will not be described here in greater detail.

FIG. 3 illustrates pulse generation from previously known pumps. As shown in the diagram, one pulse 10 is generated during each revolution (i.e., see the horizontal axis where the number of revolutions V is shown). The amplitude of each pulse is shown on the vertical axis. For the majority of the revolution time, there is no pulse generation.

FIG. 4 shows output from a pump that is arranged and configured in accordance with certain features, aspects and advantages of the present invention. As shown, the pump delivers three pulses of medium or flow pulses 11, 11′, 12, 13. It can be seen from FIGS. 3 and 4 that the amplitudes of the pulses differ considerably and that the amplitude of the pulse 10 is approximately three times as large as the amplitude of the pulses 11, 11′, 12, 13. Thus, with a pump that is arranged and configured in accordance with certain features, aspects and advantages of the present invention, the pump is less likely to cause damage to either itself or on the system in which the pump operates.

FIG. 5 schematically shows a construction of an actuating device 14 used in the pump. The actuating device 14 can be rotated by a rotating shaft 15. In the illustrated configuration, the actuating device comprises a Reuleaux triangle that has three corners 14 a, 14 b and 14 c. The number of corners can vary and can be greater than three, provided that the number is odd (e.g., five, seven, etc).

In the embodiment of FIG. 1, the Reuleaux-shaped cross section of the actuating device 14 acts upon a piston arrangement that has two pistons 17, 17. Each piston 16, 17 is schematically shown and comprises a carrier device 18 that, in the illustrated embodiment, is in the form of a yoke. The yoke construction preferably comprises flanges 18 a, 18 b. See FIG. 5. The triangular cross section of the actuating device 14 preferably comprises a cross section that has a constant width irrespective of the rotational position. Thus, the actuating device 14 determines the different positions of the pistons 16, 17 in the cylinders 19, 20 associated with the pistons.

The pump housing comprises a first partial space 21, in which the actuating device 14 and the carrier device 18 are arranged and operate. The pump housing also comprises a number of second partial spaces 22 in front of the cylinders 19, 20 in which the pistons 16, 17 operate. The pistons 16, 17 can assume first positions in the partial spaces (see the position of the piston 16). The pistons 16, 17 also can assume partially projecting second positions in the cylinders (see the position of the piston 17). The carrier devices 18 are provided with elongated holes 23 (shown in dashed lines) in association with the rotating shaft 15. The elongated holes 23 preferably are elongated in the longitudinal or axial direction of the respective one of the pistons 16, 17 in order to enable each piston 16, 17 to move between the first and second positions.

FIG. 6 illustrates the actuating device 14 interacting with four pistons 24, 25, 26, 27 that are arranged in pairs on the carrier devices 28, 29. The cylinder-shaped parts 30, 31 and 32, 33 with the second partial spaces are arranged opposite to each other in the illustrated housing 34. In most other respects, the design and function correspond to what is shown in FIG. 5.

FIGS. 7 and 8 illustrate an embodiment with a piston 35 and an associated carrier device 36. The actuating device 14 (with its generally constant width cross section and its peripheral surface 37) acts upon the flanges 38, 39 of the carrier device in generally the same way as described below. Thus, the piston 35 can move between an inserted position (see FIG. 7) and a completely or partially projecting position (see FIG. 8).

With reference to FIG. 9, a piston is indicated by 39 and the actuating device by 40. A yoke on the carrier device is indicated by 41 and the housing that encloses the arrangement has the reference numeral 42. The rotating shaft is indicated by 49 and the associated bearings in the housing 42 are indicated by 44, 45. A seal for the outer bearing 45 is indicated by 46. The motorcycle's motor drives an output shaft 43 from the gearbox. The output shaft 43 drives the rear wheel of the motorcycle via a sprocket 48 and the chain 3 drives the motorcycle's rear wheel via the sprocket 48 and the chain 3 and drives a shaft 49 via a carrier device 47. The bearings of the shaft 49 in the motorcycle are not shown specially but are constructed in any suitable manner. The carrier device 47 can drive the sprocket 48, in which case the sprocket 48 is arranged, in turn, to transfer the drive movement from the chain 3 to the output shaft 43 by means of a shaft 49. The first partial space in the housing has the reference numeral 50.

FIG. 10 shows an example of a construction with the piston 51 arranged in a way such as that described above in combination with a carrier device, one flange of which has been indicated by 52. Ducts 54, 55 from the respective second partial spaces 56, 57 are arranged in the housing 53. The actuating device is indicated by 58. An inlet for medium that is to be pressurized is indicated by 59. The inlet leads into the first partial space 60 and the incoming flow of medium is given a certain overpressure in order to ensure sufficient delivery of medium to the first partial space 60.

Each piston comprises an outer cylinder 51 a and a central part 51 b that extends in the longitudinal direction of the piston. The central part 51 b has, at its upper portion, a part 51 c and the piston is arranged with a cover 51 d that can move in relation to the cylinder 51 a. The upwardly displacement of the cover 51 d can take place against the action of a spring, for example, a spiral spring 51 e. In addition, the piston 51 is provided with longitudinal holes, for example five longitudinal holes, one of which is indicated by 51 f, that extend in the longitudinal direction of the piston 51. The arrangement with the piston is such that when the piston assumes its fully inserted position in the partial space 56, the cover 51 d closes the passage 51 f. When the piston 51 moves towards the position in which it is partially projecting out of the second partial space 56, the overpressure on the medium in the space 60 is able to lift the cover 51 d and, during this movement of the piston 51, medium can flow from the space 60 to the upper side of the piston 51. During the movement caused by the actuating device 58 towards the fully inserted position of the piston 51, the medium transferred to the outlet 61 can, in this way, be forced via the duct 54 to the outlet 61 in the cylinder housing 53. A pulse of medium is obtained in this way.

A valve or a valve arrangement preferably is arranged at the outlet 61, as shown in FIG. 11. The valve arrangement is connected to the ducts 54, 55 that, in turn, are connected to the partial spaces 56, 57. The valve arrangement preferably comprises a non-return valve arrangement for each internal duct 54, 55. The nonreturn valve arrangement can comprise a cover or shims 62, 63 that operate against the effect of a spring which can take the form of, for example, a spiral spring 64. The valve has a central part 65 arranged with openings 66. The duct 54 can be connected to the openings 66 via one or more duct parts 67, against the opening of which the device 62 makes contact by the action of the spring 64. In a corresponding way, the duct 55 can be connected to the openings 66 via a duct part 68 against the opening of which the device 63 makes contact by the action of the spring 64 that can be common to the covers 62, 63.

When the piston that operates in the space 56 generates a pulse of medium that enters the duct 54, the device 62 is pressed downwards in the figure and opens the duct 67, with the result that the pulse of medium can flow in through the openings 66 and out in the direction of the arrow 69 through the outlet 70 of the valve or the housing towards the unit that drives the front wheel. When the pulse of medium is forced out via the outlet, the spring 64 thereafter returns the device 62 and closes the duct 67. In a corresponding way, the device 63 is acted upon and opens the duct 68 when the piston 51 generates its impulse via the duct 55. The device 63 returns in a corresponding way to the position shown in FIG. 11 when the pulse is achieved. 55 a in FIG. 10 represents the opening between the partial space 57 and the duct 55.

FIG. 12 shows that the Reuleaux triangle has a constant width, where the distance between each corner (14 a, 14 b, 14 c) and the opposite part of the peripheral surface (37, 71) perpendicular to this corner is essentially the same distance irrespective of its rotational position. The periphery 71 of the cross section (see also 37 in FIGS. 7 and 8) is composed of partial peripheries 71 a, 71 b, 71 c that have essentially the same radius R. Irrespective of the rotational position of the actuating device or of the curve of constant width around the rotating shaft, the distance indicated by R will always be the same.

FIG. 13 shows the case when the cross section or the periphery 71 is provided with an additional layer 72 that has a nose radius r. The total width for the curve of constant width will thus have the value of 2r+R. By the introduction of the layer 72, this can be rounded off and a less damaging interaction can be obtained with the flanges (see 18 a and 18 b in FIG. 5) of the carrier device.

It is recognized that the pump principle has a more general application than being utilized for motorcycles of the above-described type. In an embodiment, the new pump arrangement can be arranged to supply medium to more than one hydraulic system, for example two, three, four, etc, hydraulic systems, that do not interact with each other in association with the provision of medium. Examples of hydraulic systems for, for example, motorcycles, include hydraulic systems for driving the front wheel, for controlling anti-locking brakes, for active control of steering dampers, etc. The arrangement can be divided between oil supply, oil cooler, oil filter, etc, without there being any interaction between the different hydraulic systems 73, 74 and 75 that are connected to second partial spaces as described above via ducts (see the broken lines in FIG. 6). Preferably, the pump supplies fluid at a high pressure, such as, for example, about 350 bar or the like.

The invention is not limited to the embodiments described above as examples, but can be modified within the framework of the following claims and concept of the invention. 

1-10. (canceled)
 11. A hydraulic pump arrangement comprising a housing, the housing defining a first partial space and a second partial space, a rotatable input shaft extending into the first partial space, an actuating device connected to the rotatable input shaft so that rotation of the input shaft causes rotation of the actuating device, the actuating device adapted to contact at least one axially moveable piston, the actuating device being arranged in the first partial space of the housing, the second partial space being generally cylindrical, the at least one piston being axially moveable within the generally cylindrical second partial space and being adapted to generate a flow pulse of medium, the second partial space comprising at least one medium outlet and at least one medium inlet, the actuating device comprising a cross section comprising at least three corners, each corner being spaced from an opposite peripheral surface of the cross section by a first distance, the first distance being the same along the opposite peripheral surface, the peripheral surfaces of the actuating device being arranged to interact with at least one carrier device that is connected to the at least one piston, the outlet from the second partial space at the upper side of the at least one piston is connected to a valve arrangement arranged to pass the flow pulses generated by the at least one piston.
 12. The arrangement as claimed in claim 11, wherein one or more second partial spaces are connected to a first hydraulic system and one or more second partial spaces are connected to a second hydraulic system that is not in fluid communication with the first hydraulic system.
 13. The arrangement as claimed in claim 12; wherein the valve arrangement comprises at least one spring-loaded device that is adapted to be opened and closed to control flow through the valve arrangement.
 14. The arrangement as claimed in claim 11, wherein the at least one piston is provided with an internal passage extending between an underside and an upper side of the at least one piston, a part acted upon by a spring is adapted to close the passage against the action of a spring when the part is in a first position and the part adapted to enable the passage to open when the part is in a second position.
 15. The arrangement as claimed in claim 11, wherein the at least one carrier device comprises a yoke that cannot rotate but that is able to move in the longitudinal directions of the at least one piston, and the actuating device rotating in relation to flanges of the yoke in response to rotation of the shaft.
 16. The arrangement as claimed in claim 11, wherein the at least one piston comprises two or more pistons.
 17. The arrangement as claimed in claim 11, wherein the cross section comprises an odd number of corners.
 18. The arrangement as claimed in claim 1, wherein the pump arrangement is reduced in volume and is positioned on a motorcycle in a space located on one lateral side of the motorcycle and between an attachment point for a rear wheel pivot arm and a motor. 